Diffuser



Sept. 22, 1942; F. L. SLADE DIFFUSER Filed Aug. 3, 1940 5 Sheets-Sheet 1p 22, 1942 F. SLADE- 2,296,314

DIFFUSER 'Filed Aug. 3, 1940 5 Sheets-Sheet 2 FQ L. sLADE r 2, 96,314-

' DIFFUSER r I Filed-Aug. 5/1940 5Sheets-Sheet4 Sept- F. L. SLADE2,296,314

DIFFUSER Filed Aug. 3, 1940 5 Sheets-Sheet 5 Patented Sept. 22, 1942UNITED STATES PATENT OF FlCE 'azaam V V We. 8 :23 0. Application August3, 1940, Serial No. 350,953

, 13 Claims. The invention described herein may be manufactured and usedby and for the United States Government for governmental purposeswithout the payment to me 'of any royalty thereon.

This inventionv relates to the art of ventilation and hasmoreparticularly to do with methods and apparatustfor discharging or.diffusing air or other conditioning gases or vapors into the ambientatmosphere of an enclosure, such as a marine vessel, a vehicle, or. aroom of a building.

The principal object of the invention is to provide new and improveddevices and methods for the introduction and diffusion of ventilating orconditioning gases into the ambient medium, with such acontrol of thevelocity and direction or flow of the introduced-gas as to substantiallyreduce or eliminate noise and to obtain a thorough and rapid mixing-andscrubbing eifect without giving rise to undesirable drafts in thehabitable portions of the enclosure being ventilated or .conditioned.

Basically, the invention involves the discharging of a gaseous fluidinto the ambient medium in such a way as to set up a return flow in theresulting mixture of ambient and introduced gases, whereby a proportionoi these gases is returned into or adjacent the outlet orifice of thedischarging or difiusing member or nozzle, and then redischargedand-recirculated in the enclosure, thus effecting a very eflicientmixing or. scrubbing action between the two fluids.

Prior proposals looking toward the attainment of similar eflects havebeen made, but these have necessitated the provision of mechanical meanssuch as a plurality of overlapped or periorated walls or vanes toprovide a kind of injector device, and these expedients have not provedto be as efiicient or as tree irom noise and drafts as the comparativelysimple arrangements which characterize the present invention.

- The fundamental provisions of the invention include a substantiallycylindrical discharge or diffuser member into which the incoming ventilating or conditioning medium is introduced tangentially from the supplyduct which traverses the building or other structure carrying the in-'stallation. This tangential introduction of the gas creates a whirling,constantly expanding, hollow, conical jet of fluid, which, due to thenovel arrangement and proportioning of the device under the principles.of the invention, sets up a vortex movement which of itself induces theeflicient return flow and scrubbing action, with a substantial reductionin noise and draft, and

whereby a fluid in the liquid phase is discharged M into an ambientgaseous fluid such as the atmosphere, as, ior example, in the case oflawn sprinklers 'and the like. It has also been proposed to discharge arotating stream of air into the atmosphere of an enclosure through anarrow elongated cylindrical outlet member, either at a relativelyconstant high velocity or at an increasing velocity through acontinually contracting system; the only objective being to iorce theair into the chamber or enclosure in the ttorm of an ordinary rotaryjet, which is obviously of some slight advantage over a straight lineintroduction of the fluid. Such a proposal, howevenindicates .noconception oi the principles oi the present invention, nor does itinvolve the novel qualifications and structural'limitations which theapplicant has determined by much experimentation as being necessary inproducing the effects described.

As will be developed in detail as the description proceeds, it isnecessary in order to attain the return flow scrubbing effect by meansof the fuser member bear a ratio to that of the outlet orifice thereofwhich will fall within certain limits. If the discharge cylinder is toolong with ,respect to its diameter, the desired. vortex will disappear(as, indeed, will the rotary flow itself if the length is inordinatelyincreased) and ii the length of the difiuser is too short, the air willspill over the rim of the diffuser before the whirling is efiectivelyinitiated.

If the normal outflow is unobstructed, the vortex will be formed withinthe mouth 0! the outlet orifice of the discharge member or diffuser, andthe velocity, of the air as measured across any diameter of the orificewill be at a maximum adjacent the periphery where an annular outflowsection is observed; then at the inner margin 01 this annular section, apoint oLzero velocity is found; and within this circle of zero velocity,the velocity of air within the plane of the orifice is found to benegative, 1. e., an aspiration of air from the enclosure is takingplace. This inwardly moving air is mixed .with the treating air from thesupply duct and is again discharged through the annular peripheralportion of the orifice.

The invention in its preferred form contemplates the provision of acylindrical discharge,

element having an inlet connection of either constant or increasingrectangular cross section; but within the broad scope of the inventionmay be included discharge elements of somewhat frustoconical shape, orthose having round bottom portions; and the inlet sections may also beof circular or elliptical cross section.

By positioning certain diverting elements at the circle of zero velocityadjacent the plane of the orifice, certain variant eifects in thedirection of flow of the introduced air may be attained withoutdestroying the vortex and aspirated return flow, and these features arealso comprised within .the scope of the invention.

Another object of the invention is to provide in the diffuser members,novel control dampers and operating means therefor, certain embodimentsemploying two or more dampers permitting the mixing of a plurality ofdifferent treating media in a single diffuser.

Other objects of the invention include the provision of diffusers havinginclined outlet orifices, and others having outlet orifices at both endsof the cylinder; and also various combinations of the diffuser memberswith lighting fixtures whereby not only an improved ornamental effect isattained, but also certain structural, functional, and utilitarianfeatures result.

Other objects and features of novelty will be apparent from thefollowing specification when read in connection with the accompanyingdrawings in which certain embodiments of the invention are illustratedbyway of example.

The present application is a continuation-inpart of my copendingapplication Serial No. 204,636, filed April 27, 1938.

In the drawings:

Figure 1 is a view in horizontal cross-section of a portion of aventilating duct with a simple form of outlet member or diffuserembodying the principles of the invention, attached thereto;

Figure 2 is a view in side elevation of the same structure;

Figure 3 is a view in side elevation of a doubleended diffuser;

Figure 4 is a similar view of a difiuser having an inclined outletorifice:

Figure 5 is a fragmentary view in vertical section of the outlet end ofa difluser showing a grille having a diverting blade attached thereto;

Figure 6 is a view in vertical section of a diffuser of the practicalcommercial form having a damper of novel type applied thereto;

Figure 7 is a bottom plan view of the diffuser shown in Figure 6, with aportion of the outlet grille broken away;

Figure 8 is a fragmentary sectional view taken substantially on line8-48 of Figure 6;

Figure 9 is a vertical sectional view through a diffuser member havingtwo inlets and associated damper controls;

- Figure 10 is a fragmentary horizontal sectional view of the diffusershown in Figure 9;

tary views similar to Figure 10 but showing adjusted positions of thetwo dampers;

Figure 13 is a vertical sectional view of a diffuser having a pluralityof inlets occupying different planes;

Figure 14 is a bottom plan view of the same device with a portion of theoutlet grille broken away;

Figures 15 and 16 are vertical sectional views showing modified forms ofdiffuser cylinder, and outlet vanes;

Figure 17 is a view in side elevation of a diffuser having afrusto-conical body portion;

' Figure 18 is a vertical sectional view showing a diffuser in which alighting fixture and damper control are combined; and

Figure 19 is a fragmentary sectional view taken on'line l9i9 of Figure18.

Referring now more particularly to Figures 1 and 2 of the drawings, inwhich an elementary form of the invention is illustrated, it will beseen that the supply duct is indicated generally by the referencenumeral Ill. The discharge or dlfiuser member attached to the duct isdesignated i2 and is provided with the short, tangentially disposedinlet conduit l5. In this embodiment the inlet conduit is of arectangular cross-section and is secured to the supply conduit it at thejunction of the larger portion l6 and the continuing portion ll ofdiminished section and capacity. The duct I0 is of the velocity type,but a plenum type of supply duct may be employed if desired. The inletsection I5 is attached to the duct and aligned with the duct in such amanner that a portion of the air flowing through the duct is cut on fromthe main How of air and caused to flow in a direction parallel to themain flow in the duct and thereby diverted into the cylin ri l part ofthe diffuser tangentially thereto'so as to set up a spiral whirling orrotation of the air within the diffuser. The remaining air flowingthrough the supply duct i'ii continues through the section I! to thenext point of take-oil whereupon another portion of the delivered gas ispassed tangentially into the next difiuser along the line, with acorresponding diminution of dimensions of the supply duct.

The delivered air or gas rotates helically about the interior of thediffuser l2 and passes outwardly of the circular orifice 20 of thediffuser in the form of a constantly expanding cone of rotating gas ofcontinually diminishing velocity. The outgoing cone of gas is indicateddiagrammatically at 25 in Figure 2 of the drawings and the section ofthe diffusing jet of gas is indicated by the same reference numeral inFigure 1.

The whirling cone of delivered gas sets up a vortex within the interiorthereof which results ity. outwardly of this circle the newly intro-Figures 11 and 12 are diagrammatic fragmen- 7 duced gases and therecirculated gases are being discharged in the expanding hollow cone,and within this neutral circle the introduced gases and aspiratedportions of the surrounding medium are being returned toward the outfloworifice.

Although the general direction of flow of the Velometer readings atterminal face of diflusef;

readings and may fluctuate between reasonable panding taper.

form of the invention selected at random. Alon the diameter W! at theoriflce plane 2| of the i difluser II, are the stations 1,; 2.3, 4, and5. Sim-n ilarly, along the diameter YZ are corresponding: ly disposedstations 1. 2, 3, 4, and station 3 be--v ing common to both diameters.The tabulation shows the velometer at dlflerent points, is a positivereading indicatin outflow of gas and a negative reading the inflow. mvalues given are in ieet per minute. 7

V inlet velocity 1890 F. P. M.

I Diameter Diameter '1 +1150 +1750 2 GG) -550 3 -660 --6(Xi 4 -d0() -6)s +1850 +1800 The condition of the gases within the room or enclosureadjacent the diffuser may be determined irom the following tabulation inwhich similar average velometer readings are given for the test stations10-16 inclusive as shown in Figure 2 of the drawings. The test stationswere selected at approximately two and one-half feet from the orlflce20, stations 12 and 14 being directly below the margins of the diffuser;stations 11 and 15 being at somewhat less than 30angles from theadjacent stations 12 and 14 respectively; and stations 10 and 16'beingjust outside of the 30 line.

Average oelometer readings at points spaced from outlet of difiuser m 0l1 +150 12 1'4 14 so 15 16- 0 As indicated, these values representaverage 5'5 limits, but they clearly follow the pattern suggested by thedescription and the illustrations.

It has been found by extensive experimentation that in order. to attainthis return flow effect and its consequent valuable scrubbing actionbetween the introduced gas and the ambient fluid, with a minimum ofnoise and draft, the entire discharge system from the mouth of the inletmember I! to the point of furthest movement of the introduced air shouldbe of exthat is, the velocity. of the fluid should diminish continuallywith a corresponding expansion in the olume or capacity oi the system.It has been determined that the physical characteristics ofthe'dlfluser, in order to attain this result, should fall within thefollow- I oi gasset by the difluser aretically indlcatedinthe drawings.

len h oi the diiluser i to its diameter should lie between 0.75:1 and.2:1,'and this ratio should never exceed 3:1.

The deleterious eiiects oi exceeding the upper and lower limits or theseratios may be explained as follows. when the proper "taper of thediffuser system is upset by the provision of a 7 too shallow cylinder,the tangentially introduced gas will spill over the margins of theoutlet oriflce II between the points Y'and Z. in the counterclockwisedirection as yiewed in Figure 1, before the proper whirl or helicalrotation within .the diiluser-is attained. This, of course, will destroythe vortex and aspirating eilect. It the ratio of the outlet area tothe' inlet area is too small, the outlet velocity will be too high, and

the only result will be the introduction of the gas into the ambientfluid in the form. 0! a narrow whirling solid cone; and it the height orlength oi the difl'user is too'great with respect to the diameter, thewhirling eii'ect will be lessened and ii the length were continued to anexcessive degree, this eflect would flnally disappear and a straightlongitudinal flow of air would result. a

The principles of the invention which involve the mixing eflect justdescribed, may be embod-- led in various. modifications, one of which isshown in a somewhat elementary form in Figure 3 or the drawings in whichthe difluser cylinder 40, led by the inlet section ll, is open at bothends inorder to provide two discharge cones A2 at either endo thedevice. It will be immediately apparent that in the case of thisdoubleoriflced cylinder, the best ratios 0! length to di- 'ameter willbe approximately double those already stated in connection with thesingle outlet embodiments. It is obvious that in all of the embodimentsillustrated and described, the direction of discharge may be upwardly,downwardly, or horizontally in any direction, according to the nature ofthe enclosure and the particular eflect desired. 7

, In Figure 4 of the drawings, there is illustrated a diffuser cylinder45 in which the oriflce plane 48 is inclined with respect to the axis ofthe diffuser, with the result that an inclined discharge cone and vortexindicated at 48 is iormed.

By the provision of suitably shaped and positioned bailies or vanes, theexpanding discharge cone may be altered in order to widen it and flarethe stream of introduced'fluid toward a plane parallel with the outletplane. For example, it may be desirable,.when the diffuser is returnflowof gases. At the circle of zero velocity between the discharging andreturning gases,

an outwardly flared vane or baiile 55 is secured to the grille 5| ormade integral therewith. This curved bame tends to flare or widen thecone of discharging gases as indicated by the arrows, without disturbingthe aspirating effect of the arrangement at all. It will be understoodthat the arrows in Figure 5, and also in certain of the other figures,indicate the general direction of flow .of the bodies otfluid which,however,

1 have a rotating or circular movement within themselves.

In Figures 15 and 16 0! the drawings, other modifications ofthe difluserare shown which also employ bailles such as indicated in Figure 5. InFigure 15, acylindrical diffuser body I is illustrated, having an inletpassageway SI of rectangular cross-section. The flared vane I2 has thesame general effect on the flow of introduced fluid as the vane 55 inFigure 5. This device is not provided with a grille, however, and thevane 62 is secured to the body it of the diffuser as by means of therods or bolts 64. Conical baffle 65 is secured to the bame 62 as bymeans of the supports 66 and is so shaped as to conform approximately tothe natural lines of flow of the returning or aspirated fluid. Thebaflle 65 is designed, however, to aid in streamlining the return flowand prevent the accidental formation of eddy currents, and may also beso positioned as to prevent the return of the fluids to a very greatextent into the mouth of the diffuser.

In Figure 16 of the drawings the cylindrical shape of the diffuser it ismodified to some extent to form a bowl like or rounded bottom portionii, and the inlet connection I2 is of circular cross-section conforminggenerally to the curvature of the portion ll. Otherwise the outletstructure is exactly the same as that shown in Figure 15.

As heretofore suggested, the shape of the diffuser body need not beexactly cylindrical, and the frusto-conical shape of the diffuser shownat E5 in Figure 17 of the drawings conforms more nearly to thetheoretical, constant expansion or "taper" of the diffusing system. Thisdiffuser is fed by an inlet connection It which is, of course, shaped toconform to the surface of the diffuser body.

In order to control the flow of gas introduced into the diffuser,suitable damper arrangements are provided. One eminently satisfactoryembodiment of this control means is illustrated in Figures 6, 7, and 8of the drawings. The diffuser body in this case is indicated by thenumeral 8E3, and, for convenience in manufacture, may be pressed from asingle sheet of metal. The margirl of the diffuser is flanged as at 8!and a stamped grille 82 may be secured thereto as by means of the screws83. Centrally of the grille 83 there is provided an opening throughwhich the control shaft 85 for the arcuate damper plate 86 may pass. Theinner end of the shaft 85 is rotatably secured within the perforatedsaddle bearing strip 87. Extending from spaced points along the innerportion of the shaft at are the tubular portions 80 of the telescopingstrut members st. These members also include the rods ti which arereceived within the tubes b8 and have their outer ends rigidly securedto the damper plate 86. A coil spring ts extends between the damper andthe end of the tubular member 88 in order to urge the struts 99 towardextended.

position and press the damper plate 88 firmly against the inner surfaceof the diffuser. The inlet section @5 of the diffuser is arrangedtangentially and forms with the surface of the member $8 a rectangularopening 96. The area of the damper 86 is, of course, sufllcient tooverlap the margins of this opening.

Upon the outer end of the control shaft d5 there is secured a handle M0for rotating the damper element. Within the confines of the grille 82there is rigidly secured to the shaft 86 a radial arm IOI which isdesigned to cooperate with stop elements secured to the grille 82 ineither direction. The central portion of the grille 02 is provided withan arcuate slot It: as most clearly shown in Figure 8 of the drawings,and at the proper points along this slot are secured the bolts I as bymeans of the nuts I. The inwardly extending shanks III! of the boltsextend across the plane of rotation of the arm Ill and prevent itsmovement beyond the points at which the stops are secured. The stopmembers are so positioned as to permit the damper to swing from the openposition shown in solid lines in Figure 7 of the drawings to the closedposition indicated in dotted lines.

The grille 82 in this embodiment is provided with a plurality ofopenings H0 through which the fluids may pass in their inward andoutward directions as heretofore described. The central solid portion ofthe grille is provided with a cover plate or a cap ill and a springwasher H2 is disposed between this cap and the handle portion I00. Bymeans of this damper element, the flow of fluid may be entirely out off,or any degree of opening provided.

In some cases it is desirable to supply a plurality of fluids to anenclosure, these fluids having different properties as relate totemperature, humidity, etc., and in Figures 9-14 of the drawings thereare illustrated certain embodiments of the invention includingprovisions for the introduction of gases from two diflerent sources andhaving different properties, into a single diffuser or outletarrangement.

In the embodiment illustrated in Figures 9-12 inclusive an outletstructure is provided for attachment to superposed ducts, the diffuserbody :26 being provided with tangential inlet connections I22 and 826,both having openings upon the same side of the difiuser body and beingprovided withdampers designated, respectively, by the numerals I25 andlit. A grille H8 is applied to the outlet orifice of the diffuser I20and passing axially therethrough is the control shaft I30 which has abearing i3l for its inner end. A pair of struts 832, correspondingexactly in construction and function to those illustrated at 90 inFigures 6 and 7 of the drawings, are provided adjacent the inner end ofthe control shaft m. Surrounding the shaft I30 is the tubular shaft G35which extends for approximately half the length of shaft H30. Struts I36similar to those shown at I32 extend from this tubular shaft I35 tothedamper E26.

Pinned to the shaft H30 adjacent its outer end,

is the bevel gear Mt which is continually in mesh order to.limit themovement of the damper in with the bevel pinion Mi which is carried bythe bracket I42 secured to the grille i28. Another bevel gear M4 isadjustably secured to the tubular shaft. I35 as by means of the setscrew I45. Relative rotation of the tubular member and the gear I isprevented, by means of the pin E46 secured to the gear M4 and working inthe slot provided in the tubular shaft 835, when the set screw M5 isreleased for the purpose of sliding the gear Md along the tubular shaftI35 in order to adjust the relative positions of gears ME, I, and M4.Any desired initial relative setting of the two dampers H25 and MS maybe attained by the adjustment of the gear hi l with relation to thestationarily supported gear MI by means of the adjusting devices justdescribed, and it is obvious, by manipulation of the handle 50 securedto the end of the operating shaft I30,

will be completely closed, and any intermediate v proportioning of flowthrough the two inlet ducts between these extreme positions can beattained. In Figure-1O of the drawings the damper I28 is shown in itsopen position and the other damper 5 inlet conduits. Figure 12illustrates a position I I88 in. which both dampers are closed. Thisposition may be attained by a suitable relative adjustment of thecontrolling shafts.

' In the embodiment illustrated in Figure 13 of the drawings, the twosupply ducts for the difl ferent introduced fluids are disposed in thesame plane and the inlet conduits I88 and IN are applied to'the diffusershown in Figure 14.

I82 at different angles as The openings I84 and I88 from these conduitsinto the diffuser m are spaced peripherally of the surface of thediffuser and are controlled by the dampers I81 and I88 which are fixedin their relative positions since the telescoping spring pressed strutsI'III are rigidly secured to the control shaft I12. The con- ,trol shaftis operated by means of a handle I14 "and passes through the outletgrille I18 in the usual way. Both dampers are shown in closed positionin Figure 14 and it is obvious that by rotating the 'handle I14 in aclockwise direction as seen in Figure 14, the opening I88 from the ductI8I,wi1l be uncovered and the damper I81 will move from the opening I84in the duct I88. when the rotation is continued so that the damper I88closes the duct I88, flow will occur 7 having a free and unobstructedopen end comfrom the duct I8I. Further rotation ofthe combined damperswill open both ducts for an equal mixture of the two fluids. Stillfurther movement in the same direction will cause the damper I81 toclosethe duct III and the duct I88 will be supplying the fluid to thedifluser. By adjustment to suitable intermediate positions a, desiredproportion of the two fluids may be attained.

Certain embodiments of the invention-may be combined with lightingfixtures and novel adaptations of the control means for the diffuser forI this purpose may be arranged. In Figures 18 and 19 of the drawings, anembodiment is illus-- trated in which the difluser I88 is set into theceiling of an enclosure which is indicated at I8I.

An inlet duct I82 supplies fluid to the diflus'er and the inlet openingis controlled by means of the damper I84. Disposed centrally of thediffuser is a tubular rod or pipe I88 upon the outer end of which iscarried an electrical socket I88 into which a light bulb I" maybeplaced. The pipe I88 is rigidly secured to the base of the diffuserI88 as by means of the nut I88, and may also serve to hold the diffuserI88 in its position by securing it to the outlet box I88. A tubularmember I82 is disposed axially of the difluser I88 and carries. thespring pressed extensible struts I84 which support and operate thedamper I84.

28I which is supported by means of the washer 282 held in place by thenut 288 which is applied to the rod I85. The member I82 is centered withrespect to the rod or shaft I85 by means of the disc 285 which isprovided with an opensaid This tubular member is flared at its outer endas shown at I88 and is provided with a trans- 5 288 carried by the rod288. ,This'shoe moves along the inner surface of the member I80 andserves to balance the pressure of the damper I84.

Obviously the rotation of the light casing I92, I88, I81, serves toadjust the damper I84 and a limiting device is provided for stopping therotation at its fully opened and closed positions. As more clearly shownin Figure 19 of the drawings, an arm 2I8 is secured to and extendsradially from the rod I85, and adjustably secured to the disc 288carried by the member I88 are the angle brackets 2I2 and 2, which arefastened to the disc 288 by means'of the bolts 2I5. The slots 2I8 permitof a limited adjustment of these stop brackets 2I2 and 2I4 fordetermining the fully open and fully closed positions of rotation of thecombined light fixture and damper control.

It is understood that various changes and alterations may be made in theembodiments illustrated and described herein without departing from thescope of the invention as defined in the following claims. It is alsounderstood that the terms gas, air, and gaseous medium are usedinterchangeably and are intended to include vapors within their scope.

Having thus described the invention, what is claimed as new anddesiredto besecured by Letters Patent is:

1. In a ventilation system, an outlet structure for distributing air orother gaseous fluid into an enclosure with the substantial eliminationof noise and draft, said structure comprising an unobstructed inletconduit, a cylindrical member prising the discharge orifice of the"structure, inlet conduit being disposed tangentially with respect tothe perimeter of said cylindrical member, and communicating therewith,said cylindrical member being of a length equal to from aboutthreequatters to not over three times its diameter, all whereby thefluid is caused to swirl within said cylindrical member and to flow fromsaid discharge orifice in a spirally conical form for a predetermineddistance, and a portion of said flow being automatically diverted in-.wardly toward the center of the cone and back toward said dischargeorifice to again join the continued substantially conical flow ofintroduced fluid.

2. In a ventilation system or the like, an outlet and diffusingstructure for introducing a'gaseous fluid into an ambient gaseous mediumand mixin the same. with the substantial elimination of noise and draft,said structure comprising an unobstructed inlet conduit, a hollowsubstantially cylindrical member having an open end comprising thedischarge orifice of the structure, said inlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, said cylindrical member being of a length equalto from threequarters to two times its diameter, and the crosssectionalarea of the said outlet orifice being from three to five times that ofthe inlet end of the inlet conduit, and there being no diminution ofcross-section within thestructure from the last named point toward theoutlet orifice, all whereby the fluid is caused to swirl within thesubstantially cylindrical member and to flow from said discharge orificein an expanding spirally conical form for a distance from said orifice,and a portion of said flow and of the ambient medium ing 288 throughwhich the rod passes. The membeing automatically diverted inwardlytoward the center of the cone and back toward said discharge orifice toagain join the continued substantially conical flow of introduced fluid.

3. In a ventilation system or the like, an outlet and dimrsing structurefor introducing a gaseous fluid into an ambient gaseous medium andmixing the same, with the substantial elimination of noise and draft,said structure comprising an unobstructed inlet conduit, a hollowsubstantially cylindrical member having open ends comprising thedischarge orifices of the structure, said inlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, the double-orificed cylindrical dischargemember being of a length equal to from one and one-half to four timesits diamstar, and there being no diminution of crosssection within thestructure from the last named point toward the outlet orifices, allwhereby the fluid is caused to swirl within the substantiallycylindrical member and to flow from said discharge orifices in anexpanding spirally conical form for a distance from said orifices, and aportion of said flow and of the ambient'niedium beingautomaticallydiverted inwardly toward the center of each cone andbacktoward the corresponding discharge orifice to again Join the continuedsubstantially conical flow of introduced fluid.

4. In a ventilation system or .the like, an outlet and diflusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the substantial elimination of noise anddraft, said structure comprising an unobstructed inlet conduit, saidinlet conduit being of circular cross-section, a hollow substantiallycylindrical member having a closed end, and an open end comprising thedischarge orifice of the structure, the corners adjacent the closed endsof said substantially cylindrical member being rounded to correspond to.the radius of curvature of said inlet conduit, said inlet conduit beingdisposed tangentaliy with respect to the periphery of the cylindricalmember and opening into the latter at said rounded corner, saidcylindrical member being of a length equal to from about three-quartersto not over three times its diameter, and there being no diminution ofsesame fluid is caused to swirl within the substantially cylindricalmember and to flow fromsaid-discharge orifice in an expanding spirallyconical form having an annular cross-section lying adjacent theperiphery of'the outlet orifice, and a portion of said flow and of theambient medium being automatically aspirated inwardly of said orificewithin the discharge cone to rejoin the outward substantiallyconical'flow of introduced fluid, thus providing a circle. of zerovelocity between the discharge and aspiration zones of said orifice,andan outwardly flared annular vane cross-section within the structurefrom said inlet fluid into an ambient gaseous medium and mixing thesame, with the substantial elimination of noise and draft, saidstructure comprising an unobstructed inlet conduit, a hollowsubstantially cylindrical member having an open end comprising thedischarge orifice of the structure, said inlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, said cylindrical member being of a length equalto from about three-quarters to not over three times its diameter, andthere being no diminution of crosssection within the structure from saidinlet end carried by said cylindrical member and disposed at said circleof zero velocity for flattening and broadening said cone of dischargedfluid without interfering with the described aspiration phenomenon.

6. In a ventilation system or the like, an outlet and diflusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the substantial elimination of noise anddraft, said structure comprising an unobstructed inlet conduit, a hollowsubstantially cylindrical member having an open end comprising thedischarge orifice of the structure, said inlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, said cylindrical memher being ofa length equalto from about threequarters to' not over three times its diameter, andthere being no diminution of cross-section within the structure from thelast named point toward the outlet orifice, all whereby the fluid iscaused to swirl within the substantially cylindrical member and to flowfromsaid discharge orifice in an expanding spirally conical form havingan annular cross-section lying adjacent the periphery of the outletorifice, and a portion of said flow and of the ambient medium beingautomatically aspirated inwardhg of said orifice within the dischargecone, thus providing a circle of zero velocity between the discharge andaspiration zones of said orifice,'an outwardly flared annular vanecarried by said cylindrical member and disposed at said circle of zerovelocity for flattening and broadening said cone of discharged fluidwithout interfering with the described aspiration phenomenon, and aconical bailie also carried by the cylindrical member and disposedadjacent the central portion of the plane of the outlet orifice andhaving its apex directed outwardly toward the center of the aspirationzone.

- 7. In a ventilation system or the like, an outlet and diflusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the substantial elimination of noise anddraft, said structure comprising an unobstructed inlet conduit, a hollowsubstantially cylindrical member having an open end comprising thedischarge orifice of the structure, said inlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, said cylindrical member being of a length equalto from about threequarters to not over three times its diameter,whereby the fluid is caused to swirl within said cylindrical member andto flow from. said discharge oriflce in a spirally conical form, and aportion of said flow being automatically diverted inwardly toward thecenter of the cone and back toward said discharge orifice to rejoin theoutward substantially conical flow of introduced fluid, and means forcontrolling the flow of fluid from said.inlet conduit to saidsubstantially cypoint toward the outlet orifice, all whereby thelindrical member, said means comprising an arcuate damper of an areasuflicient to cover the opening between said members, and disposedwithin said substantially movement against the inner thereof, operatingmeans for said damper, and spring pressed means for urging said damperradially outwardly against the wall of said member.

8. In a ventilation system or and diffusing structure for introducing agaseous fluid into an ambient gaseous medium and mixing the same, withthe substantial elimination of noise and draft, said structurecomprising an unobstructed inlet conduit, or hollowsubstantiallycylindrical member having an open end comprising the discharge oriflceof the structure, said inlet conduit being disposed tangentially withrespect to the periphery of the cylindrical member and opening into thelatter, said cylindrical memher being of a length equal to from aboutthreequarters to not over three times its diameter, whereby the fluid iscaused to swirl within said cylindrical member and to flow from saiddischarge orifice in a spirally conical form, and a portion of said flowbeing automatically diverted inwardly toward the center of the cone andback toward said discharge oriflce to rejoin the outward substantiallyconical flow of introduced fluid, and means for controlling the flow offluid from said inlet conduit to said substantially cylindrical member,said means comprising an arcu-' ate damper of an area sufllcient tocover the opening between said members, and disposed within saidsubstantially cylindrical member for sliding movement against the innersurface of the "wallthereof, an axially disposed, rotatable operatingshaft, an extensible and contractible strut projecting-radially fromsaid shaft and support-- ing said damper on its outer end, and means forresiliently urging said damper radially outwardly against the surface ofthe wall of said member.

9. In a ventilation system or the like, an outlet and diffusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the substantial elimination of noise anddraft, said structure comprising 'a subcylindrical member for slidingsurface of the wall comprising. the discharge orifice of the structure,a plurality of inlet pamageways leading into said f member tangentiallythereto through openings in the wall thereof which are spacedlongitudinally of the member said cylindrical member being of a lengthequal to from about three-quarters to the like, an outlet I not overthree times its diameter, whereby the fluids are caused to swirl withinthe substantially cylindrical member and to flow from said dischargeorifice in an expanding spirally conical form, and a portion of saidflow being automatically diverted inwardly toward the center of the coneand back'toward said discharge oriflce toreioin the outwardsubstantially conical flow of introduced fluid, arcuate dampers forcontrolling the flow of fluid through said openings, operating means formoving said dampers about the inner surface ofthe wall of said member toopen, clou, and adjust said openings for the desired proportioning offluid entering said memher and discharged therefrom, and means forresiliently pressing said damper against said wall surface, saidoperating means including a rotatable actuating element and gearingconnecting said element with each of said dampers for movement inopposite directions.

11. In a ventilation system or the like. an outlet and diffusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the noise and draft, said structure comprisinga subthe member said cylindrical member being of a stantiallycylindrical member having an open end comprising the discharge oriflceof the structure, a plurality ofinl'et passageways leading into saidmember tangentially thereto through spaced openings in the wall thereofsaid cylindrical memberheingofalengthequaltofromahoutthreequarters tonot over three times its diameter,

whereby the fluidsare caused to swirl within the substantiallycylindrical member and to flow from said discharge oriflce in anexpanding. spirally conical form, and a portion of said flow beingautomatically diverted inwardly toward the center of the cone and backtoward said discharge oriflce to rejoin the outward substantiallyconical flow of introduced fluid, arcuate dampers for con-- trolling theflow of fluid through said openings" operating means for moving saiddampers about the inner surface of the wall of said member to open,close, and adjust said openings for the desired proportioning of fluidentering said member and discharged therefrom, and means forresiliently'pressing said damper against said wall surface. g

10. In a ventilation system or the like, an outlet and diffusingstructure for introducing a gaseous fluid into an ambient gaseous mediumand mixing the same, with the substantial elimination of noise anddraft, said structure comprising a substantially cylindrical memberhaving an open end '15 fluid,

I fluid into an ambient length equal to from about three-quarters to notover three times its diameter, whereby the fluids are caused to swirlwithin the substantially cylindrical member and to flow from saiddischarge orifice in an expanding spirally conical form, and a portionof said flow being automatically diverted inwardly toward the center ofthe cone and back toward said discharge orifice to rejoin the outwardsubstantially conical flow of introduced fluid, arcuate dampers forcontrolling the flow of. fluid through said openings. operating meansfor moving said dampers about the inner surface of the wall ofsaidmembertoopen,close,andad- Just saidopeningsforthedesiredproportioning of fluid entering member anddischarged therefrom, and means for resiliently pressing saiddamperagainst said wall surface.

12. In a ventilationsystemortheiike, anoutlet gaseous ing the same,'withthe substantial elimination of noise and draft, said structurecomprising an unobstructed inlet conduit, a hollow substantiallycylindrical member having an open end comprisingthedischargeoriflceofthestrucuimsaidinlet conduit being disposedtangentially with respect to the periphery of the cylindrical member andopening into the latter, said cylindricalmemberbeingofalengthequaltofromahoutthreequarters to not over threetimes its diameter, whereby the fluid is caused to swirl within saidcylindrical member and to flow from said discharge oriflce in a spirallyconical form, and a portion of said flow being automatically divertedinwardly toward the center of the core andback toward said dischargeoriflce to rejoin the outward substantially conical flow of introducedsubstantial elimination of stantially cylindricalmemberhavinganopen endand means for controlling the flow of fluid ate damper ofan areasuilicient to cover the opening between said members, and disposedwithin said substantially cylindrical member for sliding movementagainst the inner surface of the wall thereof, a hollow casingcontaining a source of light disposed axially within said cylindricalmember and rotatable with respect thereto, an extensible andcontractible strut projecting radially from said casing and supportingsaid damper on its outer end, and means for resiliently urgingsaiddamper outwardly against the surface of the wall of said member.

13. In a ventilation system, an outlet structure structed inlet conduit,a cylindrical member haifing an open end comprising the dischargeorifice of the structure, said inlet conduit being disposed tangentiallywith respect to the perimeter of said for distributing air or othergaseous fluid into an enclosure with the substantial elimination ofnoise and draft, said structure comprising .an unobcylindrical member,and communicating therewith, said cylindrical member being of a lengthequal to from about three-quarters to about one times its diameter, allwhereby the fluid is caused to swirl within said cylindrical member andto flow from said discharge orifice in a spirally comcal form for. apredetermined distance, and a portion of said flow being automaticallydiverted inwardlytoward the center of the cone and back toward saiddischarge orifice to again Join the continued substantially conical flowof introduced fluid,

' LSLADE.

